General statistics on site usage would be interesting. But what about all the other data that could be extracted, both on a personal and national level?

You could, for example, determine which areas are more likely to access HIV information on the NHS website. Insurance companies would like that but would it benefit the public or be in line with people's basic privacy expectations for government services?

(I'm sure Google claim that they won't add a user looking at cancer information on the NHS site to their data profile but I wonder what other insights could be generated.)